Atomic Number
111
Element 111
Roentgenium (Rg)
Roentgenium is a chemical element with symbol Rg and atomic number 111. It is named after physicist Wilhelm Röntgen. As a synthetic element, it can be created in a laboratory but is not found in nature.
Atomic Mass
282 u
Category
Unknown Classification
Period
7
Group
Group 11: copper group
Phase
Predicted solid
Density
~28.7 (predicted) g/cm3
Electron Shells
2, 8, 18, 32, 32, 17, 2
Atomic Structure
Protons: 111. Electrons: 111. Neutrons: Varies by isotope.
Electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹⁴ 6d⁹
Why Roentgenium Matters
Roentgenium helps connect atomic number 111, unknown classification behavior, period 7 trends, and electron shell structure. Its Predicted solid phase, atomic mass of 282 u, and electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹⁴ 6d⁹ make it useful for comparing bonding patterns across the periodic table.
Discovery and Occurrence
Roentgenium was discovered 1994 by Sigurd Hofmann, Gottfried Munzenberg. Roentgenium is a chemical element with symbol Rg and atomic number 111. It is named after physicist Wilhelm Röntgen. As a synthetic element, it can be created in a laboratory but is not found in nature.
Safety and Handling Context
Roentgenium has radioactive isotopes or is commonly discussed with radioactive materials. Use this page as an educational reference; real samples require qualified supervision and controlled handling.
Related Elements
Frequently Asked Questions
- What is the atomic number of Roentgenium?
- Roentgenium has atomic number 111, which means a neutral atom has 111 protons and 111 electrons.
- What is the chemical symbol for Roentgenium?
- The chemical symbol for Roentgenium is Rg.
- What category is Roentgenium in?
- Roentgenium is classified as a unknown classification and sits in period 7 of the periodic table.
Explore Roentgenium in 3D
Use the interactive table above to rotate atomic models, compare periodic trends, and move from Roentgenium to neighboring elements without losing your place.